Yeast contamination of kidney, liver and cardiac preservation solutions before graft: need for standardisation of microbial evaluation

Assessing the impact of positive cultures in preservation fluid on renal transplant outcomes: a scoping review

BACKGROUND

Infection following kidney transplantation is a significant risk factor for adverse outcomes. While the donor may be a source of infection, microbiological assessment of the preservation fluid (PF) can mitigate potential recipient contamination and help curb unnecessary antibiotic use. This scoping review aimed to describe the available literature on the association between culture-positive preservation fluid, its clinically relevant outcomes, and management.

METHODS

Following the Joanna Briggs Institute's scoping review recommendations, a comprehensive search in databases (EMBASE, MEDLINE, and gray literature) was conducted, with data independently extracted by two researchers from selected studies.

RESULTS

We analysed 24 articles involving 12,052 samples, predominantly published post-2000, 91% of which retrospective. The prevalence of culture-positive preservation fluid varied from 0.86 to 77.8%. Coagulase-negative staphylococci emerged as the most frequently isolated pathogen in 14 studies. The presence of ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), observed in two studies involving 1074 donors, was significantly associated with an increased risk of probable donor-derived infections (p-DDI). Of the reviewed articles, 14 reported on probable donor-derived infections, while 19 addressed the topic of preemptive antibiotic therapy.

CONCLUSIONS

Routine culturing of preservation fluid is crucial for the identification of pathogenic organisms, facilitates targeted treatment and prevents probable donor-derived infections. Furthermore, this approach helps avoid the treatment of low-virulence contaminants, thereby reducing unnecessary antimicrobial use and the risk of antibiotic resistance. In cases where ESKAPE or Candida species are detected, preemptive therapy appears to be an important strategy. Given that the current evidence primarily stems from retrospective studies, there is a pressing need for large-scale, prospective trials to corroborate these recommendations. This scoping review currently represents the most thorough compilation of evidence on how contamination of preservation fluids affects kidney transplant management.

Utility of deceased donor cultures in solid organ transplantation in preventing donor-derived bacterial and fungal infectious diseases transmission

Deceased donor and organ perfusion fluid cultures are obtained in order to inform recipient antimicrobial management and therefore reduce the risk of donor-derived bacterial and fungal infections. However, important heterogeneity exists in laboratory practice across organ procurement organizations and clinical management of culture results across transplant centers. While not standardized, the clinical approach to donors with positive bacterial and/or fungal cultures should be informed by the risk of donor-derived infection (DDI) and the consequence of organ non-utilization and account for potential unintended effects of antimicrobial use in the recipient. In this review, we summarize the literature on bacterial and fungal DDIs, describe the significance of positive cultures by anatomic site, and summarize current guidance on the management of positive cultures from donors or preservation fluids.

Candida chorioretinitis in renal transplant recipient with candidemia related to contaminated organ preservation fluid: A role for dilated fundus examination in its management

Infection by Candida spp is a potentially life-threatening condition among both immunocompromised and immunocompetent patients. Candida chorioretinitis can occur as a complication of candidemia and may develop into endophthalmitis if not detected and treated early, which can lead to irreversible visual loss. Here, we report on a 52-year-old diabetic woman who developed candidemia complicated by bilateral chorioretinitis following kidney transplantation. Antifungal therapy was immediately started but fundoscopic examination highlighted multiple bilateral chorioretinal lesions. Given new onset of vomiting and increased number of retinal lesions on repeat fundus examination a few weeks later, the patient underwent a positron emission tomography (PET) which revealed a mycotic arterial pseudoaneurysm at the renal graft anastomosis. It led ineluctably to transplantectomy, aneurysm flattening and vascular reconstruction a few days later. Blood cultures remained negative and fundus examination progressively showed a regression of chorioretinal lesions until their complete disappearance a few months later. Our case emphasizes the importance of a non-invasive examination which allowed to accelerate and optimize in a consequential way the management of the patient leading to her recovery after a long antifungal treatment.

The impact of preservation fluid culture on graft site arteritis: A systematic review and meta-analysis

BACKGROUND

The role of culturing the graft preservation fluid (PF) is controversial and its impact on graft arteritis development remains unclear.

METHODS

Systematic literature search retrieving observational studies comparing solid organ transplant (SOT) recipients with culture-positive PF versus culture-negative PF. The quality of included studies was independently assessed according to the ROBINS-I tool for observational studies. Meta-analysis was performed using Mantel-Haenszel random-effect models. Graft site arteritis within 180 days from transplant was selected as the primary outcome.

RESULTS

Twenty-one observational studies (N = 2208 positive PF vs. 4458 negative) were included. Among positive PF, 857 (38.8%) were classified as high-risk group pathogens and 1351 (61.2%) as low-risk pathogens. Low-risk and negative PF showed similar odds ratios. A significant higher risk of graft arteritis was found in SOT recipients with a PF yielding a high-risk pathogen (odds ratio [OR] 18.43, 95% confidence interval [CI] 7.83-43.40) compared to low-risk and negative PF, with low heterogeneity (I² = 2.24%). Similar results were found considering separately high-risk bacteria (OR 12.02, 95%CI 4.88-29.60) and fungi (OR 71.00, 95%CI 28.07-179.56), with no heterogeneity (I² = 0%), and in the subgroup analyses of the liver (OR 16.78, 95%CI 2.95-95.47) and kidney (OR 19.90, 95%CI 4.78-82.79) recipients. However, data about diagnostic features of graft arteritis were very limited, indeed for only 11 of the 93 events histological or microbiological results were reported.

CONCLUSIONS

Our results may support the performance of PF culturing and a preemptive diagnostic or therapeutic management upon isolation of high-risk pathogens. Further studies based on a reliable diagnosis of graft arteritis are needed.

Candida Contamination in Kidney and Liver Organ Preservation Solution: Does It Matter?

INTRODUCTION

Fungal infections remain a major challenge affecting outcomes after kidney (KT) and liver transplantation (LT).

METHODS

In this retrospective single center study, the incidence of Candida contamination in renal and hepatic graft preservation solution (PS) was evaluated. In addition, Candida associated infections in recipients and related complications were analyzed.

RESULTS

Overall, the PS of 1248 hepatic and 1273 renal grafts were evaluated. The incidence of fungal contamination in the PS of hepatic and renal grafts was 1.2% and 0.86%, respectively. Additionally, the hepatic PS of one patient who underwent a combined liver-kidney transplant had Candida contamination. Candida albicans was the most common organism (70.4%) and 65.4% of the patients received antifungal treatment. Candida-associated complications in the recipients was 19%. Complications in LT patients included Candida peritonitis and Candida sepsis. Two KT recipients with contaminated PS developed a mycotic aneurysm at the anastomotic site resulting in severe bleeding. The 1-year mortality in patients with PS contamination for LT and KT recipients was 33% and 18%, respectively. Although the incidence of fungal contamination of PS was low, contaminated PS was associated with a high mortality.

CONCLUSION

The results of the study suggest that PS should be evaluated for fungal growth.

Risk factors for intra-abdominal fungal infection after simultaneous pancreas-kidney transplantation: A single-center retrospective experience

BACKGROUND

Data on the risk factors and outcome of intra-abdominal fungal infections (IAFI) following simultaneous pancreas-kidney transplantation (PKT) are scarce.

MATERIALS/METHODS

A retrospective monocentric study was conducted on all patients who underwent simultaneous PKT from January 2007 to December 2016. Deep sites positive cultures for fungi during the first post-transplantation year were collected. Clinical, radiological, and microbiological data of proven and probable invasive fungal infections were analysed.

RESULTS

Among sixteen PKT patients, 15 were included. Seven patients (47%) developed an invasive fungal infection, exclusively IAFI (six proven, one probable). The proven IAFI included four peritonitis, one pancreatic necrosis with infected hematoma, and one patient with positive preservation fluid only (PF). Candida albicans (n = 4) was the most prevalent species (associated with Galactomyces candidus in one case), C glabrata, C dubliniensis, and C krusei were found in one case each. Three patients had either a positive direct examination and/or culture for renal or pancreatic PF and the culture of PF was positive for the same species that caused IAFI. IAFIs were significantly associated with pancreatic graft arterial thrombosis (5/7 vs 0/8, P = .007) and fungal contamination of PF (3/7 vs 0/8, P = .008). Among patients with IAFI, all required an early surgical revision post-transplantation [1-18 days] and six had early or delayed pancreatic graft removal. One patient died in the first post-transplant year.

CONCLUSION

IAFI is a common complication in PKT, associated with pancreatic graft thrombosis or fungal contamination of the graft PF, and can sometimes lead to pancreatic detransplantation.

Fatal aspergillosis of the renal vasculature in a combined liver-kidney transplant recipient

Invasive aspergillosis remains a problem in solid organs and haematopoietic stem cell transplants. We report a case of 12-year-old female with primary hyperoxaluria with regular haemodialysis for the end-stage renal disease. She underwent a combined liver and renal transplantation which got infected by aspergillosis. In this case study, it is speculated that the most likely source of Aspergillus was contaminated preservative solution (perfusate), resulting in infection within the donor kidney and subsequent systemic infection in the recipient. This case study calls for critical analysis and needs for the routine culture of the preservative solution before transplantation, to detect any fungal contamination and manage it prophylactically.

Risk factors for early invasive fungal infections in paediatric liver transplant recipients

Invasive fungal infections (IFIs) postliver transplantation are a frequent cause of morbidity and mortality; however, studies reporting on these infections in the paediatric population are scarce. To investigate the incidence and risk factors of IFIs in paediatric liver transplant recipients during the early posttransplantation period (≤3 months). Data were collected for all paediatric liver transplant recipients registered in a national transplantation center from 2004 to 2014. Using a stepwise logistic regression to identify independent risk factors for IFIs, a predictive model was formulated. Ten IFIs were identified in 81 liver transplant recipients (12.3%) all occurring during the first month posttransplantation. Candida species were responsible for nine cases (90%), of which four were non-albicans Candida (44%). Significant risk factors were identified; recipient of multiple blood product transfusions during transplantation, prolonged use of indwelling intravenous catheter, prolonged IV antibiotic treatment, surgical complications, pulse steroid treatment and living donor liver transplantation. The predictive model used two clinical parameters to define high-risk patients: a living donor transplantation and duration of IV antibiotic treatment (area under the ROC curve 0.918). IFIs are a significant complication occurring in the first month posttransplantation. Future studies are required to assess efficacy of targeted antifungal prophylaxis in high risk patients.

Investigating Clinical Issues by Genotyping of Medically Important Fungi: Why and How?

Genotyping studies of medically important fungi have addressed elucidation of outbreaks, nosocomial transmissions, infection routes, and genotype-phenotype correlations, of which secondary resistance has been most intensively investigated. Two methods have emerged because of their high discriminatory power and reproducibility: multilocus sequence typing (MLST) and microsatellite length polymorphism (MLP) using short tandem repeat (STR) markers. MLST relies on single-nucleotide polymorphisms within the coding regions of housekeeping genes. STR polymorphisms are based on the number of repeats of short DNA fragments, mostly outside coding regions, and thus are expected to be more polymorphic and more rapidly evolving than MLST markers. There is no consensus on a universal typing system. Either one or both of these approaches are now available for Candida spp., Aspergillus spp., Fusarium spp., Scedosporium spp., Cryptococcus neoformans, Pneumocystis jirovecii, and endemic mycoses. The choice of the method and the number of loci to be tested depend on the clinical question being addressed. Next-generation sequencing is becoming the most appropriate method for fungi with no MLP or MLST typing available. Whatever the molecular tool used, collection of clinical data (e.g., time of hospitalization and sharing of similar rooms) is mandatory for investigating outbreaks and nosocomial transmission.

Donor Derived Candida stellimalicola in a Clinical Specimen: Preservation Fluid Contamination During Pancreas Procurement

We report here a case of possible donor-derived Candida stellimalicola infection after pancreas transplantation. Candida stellimalicola, an environmental non-filamentous yeast, was isolated from both the peritoneal fluid of the graft donor and the preservation fluid of the transplanted pancreas. Interestingly, this strain exhibited high minimum inhibitory concentrations to azoles. These results justified the use of echinocandins as therapy instead of fluconazole. This switch permitted a favorable outcome. To our knowledge, this is the first report of C. stellimalicola from clinical samples and therefore the first reported case of a possible human infection. This case report highlights the need for standardized microbiological procedures in solid organ transplant settings. Moreover, it underlines the importance of using molecular identification technique when routine techniques do not allow successful identification of the pathogen. It is of utmost importance to determine sensitivity profile, even in the absence of species-level identification, because resistance to fluconazole is not uncommon, especially in emergent species.

Clinical Significance of Contamination of the Preservation Solution in Liver Transplantation

INTRODUCTION

The aim of the present study was to describe the incidence and microbiological profiles of positive cultures obtained from preservation solution (PS) and correlate these findings with infectious complications detected in the liver transplant (LT) recipient.

PATIENTS

We conducted a single-center, retrospective study between December 2010 and August 2014 among 178 LT. In all grafts, a PS culture was carried out. All the infections in the receipt until hospital discharge were collected. In patients with >1, infection was considered the most severe according to Clavien-Dindo classification.

RESULTS

PS culture was positive for bacterial or fungal agents in 79 of 178 LT recipients (44%). The most commonly cultured organisms were coagulase-negative staphylococci (64%), Enterobacteriaceae (17%), and Staphylococcus aureus (4.7%). In the 79 patients with positive PS, 49 blood cultures were requested in the period after LT. Twenty-five postoperative infections (31.7%) were diagnosed. Only 4 of 79 patients (5%) with PS contamination had a postoperative infections related with isolated microorganism.

CONCLUSIONS

Contamination of PS appears in a high percentage of liver grafts before LT, although there is a poor correlation with postoperative infections in LT recipient. In these patients, a standardized process including fungal and bacterial cultures could be useful.

Fungal complications after Candida preservation fluid contamination in liver transplant recipients

Donor-derived fungal infections can be associated with severe complications in transplant recipients. Donor-derived candidiasis has been described in kidney transplant recipients where contamination of the preservation fluid (PF) was a commonly proposed source. In liver transplantation, these fungal infections have been less explored. The aim of this study was therefore to determine the incidence and clinical relevance of Candida contamination of preservation fluid in the context of liver transplantation. A 5-year (2008-2012) retrospective multicentre study involving six French liver transplantation centers was performed to determine the incidence of Candida PF contamination. Postoperative clinical features, outcomes in recipients, and risk factors for Candida-related complications of liver transplantation were studied. Candida sp. was isolated from 28 of 2107 preservation fluid samples (1.33%). Candida albicans was the most common yeast (n = 18, 64%). Twenty-two recipients (78.5%) received antifungal therapy (echinocandins in 68%) for 7-37 days. Eight patients developed yeast-related complications (28.6%) including hepatic artery aneurysms (n = 6) and Candida peritonitis (n = 2). The 1-year mortality rate among patients after a yeast-related complication was 62.5%. The incidence of Candida PF contamination was low, but was associated with dramatic postoperative complications and high mortality. Close radiological follow-up may enable early recognition of the arterial complications associated with PF contamination by Candida.

Antifungal prophylaxis in liver transplantation: a systematic review and network meta-analysis

Invasive fungal infections (IFIs) cause significant morbidity and mortality in liver transplant recipients, but the need and best agent for prophylaxis is uncertain. A comprehensive literature search was performed to identify randomized controlled trials comparing regimens for antifungal prophylaxis in liver transplant recipients. Direct comparisons were made between treatments using random-effects meta-analysis and a Bayesian network meta-analysis was performed for the primary end point of proven IFI. Fourteen studies met inclusion criteria, reporting comparisons of fluconazole, liposomal amphotericin B (L-AmB), itraconazole, micafungin and placebo. Overall, antifungal prophylaxis reduced the rate of proven IFI (odds ratio [OR] 0.37, confidence interval [CI] 0.19-0.72, p = 0.003), suspected or proven IFI (OR 0.40, CI 0.25-0.66, p = 0.0003) and mortality due to IFI (OR 0.32, CI 0.10-0.83, p = 0.02) when compared to placebo. All-cause mortality was not significantly affected. There was no difference in risk of adverse events requiring cessation of prophylaxis (OR 1.11, 95% CI 0.48-2.55, p = 0.81). In the network meta-analysis an equivalent reduction in the rate of IFI was seen with fluconazole (OR 0.21, CI 0.06-0.57) and L-AmB (OR 0.21, CI 0.05-0.71) compared with placebo. Routine prophylaxis with fluconazole or L-AmB reduces the incidence of IFI following liver transplantation, and the available evidence suggests that the two are equivalent in efficacy.

Candida species contamination of preservation fluid-outcome of renal transplantation in 6 patients

BACKGROUND

Fungal infections are a rare but important cause of morbidity and mortality in kidney transplantation. Fungal contamination of the kidney preservation fluid may, sometimes, be the cause of these infections. However, the clinical consequences of fungal contamination of this fluid are not completely understood and literature on this topic is controversial. The purpose of this study was to determine the incidence of preservation fluid contamination by fungi and its clinical consequences.

METHODS

From June 2010 to September 2011, a prospective cohort analysis was conducted at our center, enrolling all patients who received a renal allograft and whose perfusion fluid was analyzed for microbiology sterility. Patients with perfusion fluids positive for fungi were further studied: the patients' status was assessed during regular visits and data were recorded, including clinical characteristics, infections, graft function, immunosuppressive regimen and outcomes.

RESULTS

Microbiologic, cultures of 70 kidney perfusion fluids using specific mycologic media, obtained from 74 cadaveric renal transplants (4 fluids were unsuitable for analysis), were evaluated. Six samples were positive for yeasts (8.6%), with 4 isolates of Candida albicans and 2 isolates of Candida glabrata. Four patients had no evidence of fungal infection during the follow-up period (median 321 days); conversely, 2 patients developed severe mycotic vascular complications leading to transplantectomy.

CONCLUSIONS

Perfusion fluid contamination by fungi is an elusive situation that can lead either to an unremarkable clinical course or to graft loss life-threatening situations. Routine culture of kidney perfusion fluid is critical for prompt diagnosis and early implementation of appropriate treatment.